Many commercially significant therapeutic agents are effective by the oral route of administration. Generally speaking, orally administered tablets and capsules are the most convenient, and most patient favored dosage forms. Nonetheless, there are many patients either unable or simply unwilling to take such orally administered medications. For some patients, the perception of unacceptable taste or mouth feel of a dose of medicine leads to a reflex action that makes swallowing difficult or impossible. Thus, there are many patients, including particularly pediatric and geriatric patients, that find it difficult to ingest the typical solid oral dosage forms of therapeutic agents such as compressed tablets or capsules.
Accordingly, there has been a significant research and development effort directed to the identification of alternate acceptable oral dosage formulations. Thus, for example, flavored solutions/suspensions of some therapeutic agents have been developed to facilitate the oral administration of such agents to patients normally having difficulty ingesting conventional solid oral dosage forms. While liquid formulations are more easily administered to the problem patient, liquid/suspension formulations are not without their own significant problems and restrictions. Firstly, the dose amount is not so easily controlled as with tablet and capsule forms. Secondly, many therapeutic agents are simply not sufficiently stable in solution/suspension form. Indeed, most suspension type formulations are typically reconstituted by the pharmacist and then have a limited shelf life even under refrigerated conditions. Another problem with liquid formulations which is not so much a factor for conventional solid oral dosage forms such as tablets and capsules is the taste of the active agent. The taste of some therapeutic agents is so unacceptable that liquid formulations are simply out of the question. Finally, solution/suspension type formulations are typically not acceptable where the active agent must be provided with a protective coating, e.g. a taste masking coating or an enteric coating to protect the active agent from the strongly acidic conditions of the stomach.
Particulate or pelletized forms of therapeutic agents, optionally having functional coatings, have been available either for filling capsules or in packets from which a patient can sprinkle the particulate/pelletized dose onto soft food. While use of such particulate dosage forms as a "sprinkle" composition for use on food does facilitate oral administration, that dosage methodology is also not without its limitations. The food itself can interact with the functional coatings typically used on such dosage forms to dissolve or otherwise disrupt the coating prematurely. Depending on the purpose of the coating, its premature disruption can adversely affect therapeutic efficacy and/or the taste of the food. Coating disruption can likewise occur in the mouth. The grittiness a patient encounters when utilizing "sprinkle" dosage forms on soft food encourages chewing.
In addition to the above referenced efforts to develop alternate dosage forms as a means for facilitating oral administration of therapeutic agents, the patent literature evidences efforts to develop devices intended to facilitate the oral administration of conventional solid oral dosage forms (tablets and capsules).
DuRall U.S. Pat. No. 2,436,505 describes a generally tubular straw-like device having an expanded mouthpiece for retaining the solid medication for oral administration. The device is utilized by inhaling a liquid through the tubular member similar to the normal use of a straw.
Koppenhagen U.S. Pat. No. 697,209 discloses a device for containing a liquid and suspending a solid medication. The liquid and solid medication are ingested by turning the device upright to allow the liquid and medication to move into the mouth by the force of gravity.
Sullivan U.S. Pat. No. 121,684 describes a device generally in the form of a kettle having a means for insertion of a solid medication into its spout. The spout is taken into the mouth for ingesting the liquid therein while a solid medication is inserted into the spout for flow into the oral cavity along with the stream of liquid.
Allen U.S. Pat. No. 4,581,013 describes and claims a dosing device for facilitating the oral administration of solid medicines, particularly tablets and capsules.
Notwithstanding the progress that has been made in the development of new oral dosage forms and devices to facilitate administration of old dosage forms, there is still much room for improvement in this technology area.
Accordingly, it is an object of this invention to provide an improved device for the oral administration of a dose of a therapeutic agent.
It is a further object of this invention to provide a method for administering a predetermined dose of a therapeutic agent in particulate dosage form with minimal sensed contact of the therapeutic agent with the oral cavity and with minimal disruption of functional coatings, if any, on said particulate dosage form.
It is still another object of this invention to provide an oral active therapeutic agent in a unit dosage form, packaged in a tube configured to facilitate the oral administrative of the contained therapeutic agent.
These and other objects are accomplished in accordance with this invention by use of a delivery device in the form of a tube adapted or configured to retain a unit dose of a therapeutic agent in a free-flowing form for contact with and vertical displacement by a fluid drawn through the tube by the normal sipping action of a patient. The delivery tube has a fluid inlet end and a fluid outlet end and can be constructed to have a particle retaining means in contact with the inner walls of the tube and located at a point between the fluid inlet and fluid outlet ends of the tube. The retaining means is typically constructed as a fluid permeable grid in the form of a weave, mesh, screen, sieve or slat construction. The grid is constructed to have a surface area greater than the minimum luminal cross-sectional area of the tube at any point along its length. The grid is typically constructed so that at least a portion of the grid forms an acute angle with a line parallel to the longitudinal axis of the tube. In one preferred embodiment the grid is a planar structure and has a surface area greater than the cross-sectional area of the tube at its outlet end. The therapeutic agent is located in particulate form between the grid and the outlet end of the tube. Either one or both of the ends of the tube can be adapted to receive one end of a drinking straw.
Alternatively, the tube can be configured to retain a dose of therapeutic agent in an axially discrete portion of the tube having a local gravitational potential minimum relative to adjacent axial portions of the tube when the tube is in position for oral administration of the contained dose.
In each embodiment of this invention the device is designed to allow a maximum rate of liquid flow through the tube when the liquid outlet end is placed in a patient's mouth and the patient draws liquid into the inlet end of the tube with a normal sipping action. Optionally, each embodiment of this invention is provided removable means for sealing the therapeutic agent in the tube, thus providing a convenient package form for the contained unit dose.
Use of the pharmaceutical delivery device in accordance with this invention requires that the patient place the outlet end of the tube in his mouth and the inlet end in a liquid reservoir. Normal sipping action of the patient results in the rapid and smooth flow of the therapeutic agent and the carrier liquid into the alimentary canal of the patient with minimal sensed contact of the therapeutic agent with the oral cavity.